Pre-Kreb cycle question

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MichaelXY
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Pre-Kreb cycle question

Post by MichaelXY » Sat Apr 12, 2008 4:48 am

This is kind of hard to describe, but here goes.
I am hoping someone can explain something for me. While reading about cell respiration, (pg 168 Campbell Biology 7ed) Just after glycolysis we have pyruvate (C3H3O3 as shown in book), it enters the transport protein of the mitochondrion, and upon exiting the protein CO2 is released.. According to the book we have C2H3O. NAD then comes along and snags an H, so one would expect the product to be C2H2O, but this is not the case because when the CoA is attached we have C2H3OCoA. When I look up pyruvate in Wiki the chem formula is C3H4O3 which would account for the missing H, but my question is... Why is the 4th H ion not mentioned in the book, or what am I not getting here?
Hope that made sense, and thanks.

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Post by MrMistery » Sun Apr 13, 2008 6:24 pm

There is a difference between pyruvic acid and pyruvate. Pyruvic acid has the formula CH3COCOOH. But in solution, pyruvate, like any acid, ionizes, producing yielding pyruvate(CH3COCOO-) and H+. In biochemistry we usually deal with the ionized forms of acids, because biochemistry takes place in water.
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MichaelXY
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Post by MichaelXY » Sun Apr 13, 2008 8:06 pm

Great answer, and thanks.

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